Configurations

The Delta IV launch system is available in three configurations: the Delta IV Medium+, with two or four solid rocket motors (SRMs), and the Delta IV Heavy. Each configuration is comprised of a common booster core (CBC), a cryogenic upper stage and a 5-meter-diameter payload fairing (PLF).

Payload Fairings

The payload fairing (PLF) provides a controlled, safe environment for spacecraft during ascent.

All ULA PLFs are configured for off-pad payload encapsulation, which enhances payload safety and security and minimizes on-pad time.

Delta IV offers a 5-meter-diameter PLF, optimized for the configuration and mission need. The Delta IV Medium uses a standard carbon composite bisector design. The Delta IV Heavy is available with an elongated carbon-composite bisector or metallic trisector PLF.

Propulsion

Main Engine

Design simplicity and demonstrated capability define the Delta IV RS-68A main engine. Designed and manufactured by Aerojet Rocketdyne, the throttleable RS-68A engine is the largest existing hydrogen-burning engine. Conceived using a simplified design
approach, it has fewer parts, is lower risk and has inherently reliable operation.

Nominal Thrust (sea level): 702,000 lbs

Specifc Impulse (sea level): 362 seconds

Length: 204 in

Weight: 14,876 lbs

Fuel/Oxidizer: Liquid Hydrogen/Liquid Oxygen

Solid Rocket Motors

For additional thrust at liftoff, the Delta IV Medium+ uses either two or four Orbital ATK solid rocket motors (SRMs). The SRMs are strapped to the common booster core and jettisoned in-flight for maximum performance.

Peak Vacuum Thrust: 280,000 lbf

Specific Impulse: 275.2 seconds

Length: 636 in

Weight: 74,500 lbs

Nominal Burn Time: 90 seconds

Upper Stage

Both the Atlas V and the Delta IV rely on the RL10 propulsion system to power their second stages. Logging an impressive record of nearly 400 successful flights and nearly 700 firings in space, RL10 engines, manufactured by Aerojet Rocketdyne, harness
the power of high-energy liquid hydrogen. The RL10 boasts a precision control system and restart capability to accurately place payloads into orbit.

The Delta IV employs the RL10B with the world’s largest carbon-carbon extendible nozzle for increased performance.

United Launch Alliance (ULA) today named veteran aerospace industry executive John Elbon as its next chief operating officer, succeeding Dan Collins, who had served as COO since ULA’s founding in 2006 and retired early this year.